Secret extra dog

This was an experience that happened to me while working as a sitter over the summer and I thought I would share to say please don't do this as a client! I received a booking for two doodle dogs for a three day house sitting. I'm not the biggest fan of doodles, as they tend to have behavioral issues but obviously that's no reason to turn down a gig. So, l showed up to this client's house and was immediately swarmed by three medium to large sized dogs. The owner tells me that I will actually have to sit for three dogs and not two, as the booking had said. He told me he would compensate me under the table for this. Although I agreed, I was iffy about this since this was our first booking together and I wasn't sure if I could trust this client fully. Plus, it's never nice to prepare for one thing and have another thing sprung up on you. Because of the size and quantity of the dogs, I would have to walk them two at a time, effectively doubling the work I had prepared to do. Maybe it’s on me that I even accepted the booking, but I felt like I had to. I had just driven all that way for the meet and greet and accepted the booking through the app. The clients were leaving the next day and I felt obligated to accept the request. This is somewhat unrelated, but these clients lived in a townhome off the side of a busy multi lane road, so I was stuck (as per their instructions) walking these dogs up and down a quarter mile strip of hot concrete in summer in the south until they finally pooped. Not great either. So, everything goes fine except a couple of accidents and the doodles misbehaving (fork found in kitchen), and I send my standard departure message describing everything I did before I left and emphasizing how any tip is greatly appreciated. I then added my third party payment account info so the owner could send me the money for the extra dog. One day passes, then two, and nothing. I message him again asking him to pay me for the third dog. Again, nothing. Now, I'm wondering if I should threaten legal action. I would never actually go through with this because I don't have the time, resources, or money, but in my experience a threat often does the job. However, I decided to give him one more chance, and asked whether he had received my previous two messages. Finally, after a couple of hours, he responded and paid me for the extra dog (and shorted me $2...). Never received a tip. Please never do this to your dog sitters. We deserve to know what we're being hired for and not get put in uncomfortable situations where you're forced to rely on the good will of a total stranger.